MLU for Windows

  for Windows

MLU is a Windows Application for the Analysis of Aquifer Tests and the Design of Well Fields in Layered Systems

Program characterization
Product information
Output screens
Test models
Users guide

Program characterization

MLU (Multi-Layer Unsteady state) can be used for drawdown calculations and inverse modeling of transient well flow (pumping tests analysis) in layered aquifer systems and stratified aquifers.

With MLU one can estimate selected aquifer parameters based on a best fit analytical solution to measured time-distance-drawdown data. The automatic curve-fitting algorithm computes optimized aquifer parameters and fitted drawdown results that are presented in graphs and ASCII-files.

Unlike other aquifer test analysis software, often supporting a wide variety of different solution types (e.g., Theis, Hantush, Neuman, Boulton, Papadopulos, Moench, Bouwer-Rice) for usually one and sometimes two aquifers, MLU is based on a single analytical solution technique for well flow that handles:

  • Layered aquifer systems, i.e. multi-aquifer systems (aquifers and aquitards)
    and single layered (stratified) aquifers,
  • Confined, leaky and delayed yield aquifer conditions,
  • Effects of aquifer and aquitard storativities,
  • One or more pumping or injection wells,
  • Variable discharge for each well,
  • Finite diameter well screens in any selection of aquifer layers,
  • Well bore storage and skin effect for each pumping well,
  • Delayed observation well response.

Theoretical background information on the developed and applied analytical solution techniques for multiple aquifer systems has been published in: Journal of Hydrology 90, p. 231-249 (1987) and 225: p. 1-18 and p. 19-44 (1999). You may contact the authors (hemker at microfem dot com) for a pdf of these publications. The applied non-linear regression technique is described in Ground Water (1985) 23, no.2, p. 247-253.

The MLU characteristics allow for all sorts of tests, including variable discharge tests, recovery tests, step-drawdown tests, complex tests in well fields and slug tests. It also handles partially-penetrating and large-diameter wells, bounded aquifers and double-porosity systems.

Hydrogeologists have found MLU to be very useful for quickly estimating aquifer properties such as layer-by-layer transmissivity, storativity, and vertical resistance/conductance based on aquifer testing data, and efficiently incorporating these properties into numerical groundwater flow models for advanced subsurface flow evaluations. As far as we know, MLU is the only Windows tool for evaluating aquifer response to pumping in a multi-layer aquifer system.

Product information

MLU modeling features

Saturated groundwater flow
Multiple-aquifer systems and stratified aquifers
Confined, leaky and unconfined conditions
Multiple wells
Multiple finite-diameter screens
Well bore storage and skin
Variable discharges
Delayed observation well response

Input & Output

Interactive data input
ASCII model files
Data exchange with spreadsheets
Graphs of time-variant drawdown or head
Graphs of time-variant aquifer discharge
Background raster image maps
Animated contour plots
Clipboard bitmap output
Vector-based meta-file output
XYZ-file output of contour maps
File output of computed heads of displayed time graphs
Conversion to MicroFEM finite element model file

Program Capacities

80 aquifers (layers) and 81 aquitards
1000 pumping/injection wells
100 pumping periods per well
100 observation wells
1000 drawdowns per observation well
16 parameters to be optimized in one run
User assigned names for all wells

Parameter optimization features

Automated curve fitting based on Levenberg-Marquardt algorithm
Lineair and log-transformed least squares solutions
Individual and grouped parameters to be determined in one run
Statistical data output includes standard deviations and correlation matrix

Documentation and Support 

Fully documented on-line Help
Example data files for all kinds of test types
MLU Users Guide
MLU Tutorial
Excellent customer support

Download the free LT-version of MLU for Windows. It is a fully functional, capacity-reduced version of MLU. It handles up to 2 aquifers and 3 aquitards, 2 pumping wells, 5 observation wells, while 6 parameters can be optimized in one run.

Example Output Screens



Verification and Aquifer Test Models


Flow to a partially penetrating, finite-diameter well in a homogeneous, anisotropic water-table aquifer
(Moench, 1997; Barlow & Moench, 1999)


Pumping test in a fully confined two-aquifer system
(Schroth & Narasimhan, 1997)


Water table two-aquifer system with diffusive cross flow in anisotropic aquitard
(Lebbe & de Breuck, 1995)


Water table single aquifer system with partially penetrating well
(Kruseman & de Ridder, 2000)


Double porosity aquifer with diffusive interporosity flow and fracture skin
(Moench, 1984)


Bounded aquifer modelled with image wells
(Ségol, 1994)


Step-drawdown test
(Clark, 1977)


Recovery test


Multiwell slug test, pulse interference test
(Butler & Liu, 1997).

MLU Users Guide and MLU Tutorial

For more detailed information on how to input data to MLU and format output
see the MLU Users Guide.

For more detailed information on how to construct MLU models and use MLU
to analyze multilayer aquifer tests based on real world examples
see the MLU Tutorial.

Review in Ground Water

MLU for Windows has been reviewed by the NGWA Ground Water Journal
in the Software Spotlight Column, which is edited by Chunmiao Zheng
Ground Water 50, No. 4, p. 504-510. (download pdf = 1.4 MByte)
It received the following ratings on the scale of 1 (worst) to 5 (best):

    Capability 4.8
    Reliability 4.5
    Ease of use 4.0
    Tech support 5.0

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